3-1 CONTROL SYSTEMS BITS

                                                      CONTROL SYSTEMS

                                                            JNTUH BITS   

                                                      UNIT-I: Introduction

NOTE:  Don't think that these bits only will be repeated in first mid.Prepare concepts thoroughly then solve these bits .These bits to cross check your knowledge in subject. 

 1. The principle of homogeneity and Superposition theorem is applied to [a ]

(a) Linear Time Invariant System (b) Non Linear Time variant system

(c) Linear Time variant system (d) Non Linear Time Invariant system

2.  Any physical system which does not automatically correct for variation in its output is called [a]

(a) Open loop (b) closed loop (c) unstable (d) stable

3.  Transfer function of a system is defined as [ b  ]

a) ratio of Laplace transform of input variable to the Laplace transform of the output variable when all initial conditions are zero

b) ratio of Laplace transform of output variable to the Laplace transform of the input variable when all initial conditions are zero

c) Laplace transform of the output variable when all initial conditions are zero

d) Laplace transform of the input variable when all initial conditions are zero

SECTION-II: Fill in the blanks

1.      The elements of a mechanical rotational system are  J,B,K

2.      The transfer function of a feedback control system is  G(s)/ [1+G(s) H(s)]

       3.An example of closed loop system is  Air Conditioner or Microprocessor based traffic control system

                                  

                                 UNIT-II:  Transfer function Representation

1.  The equation based on which a Signal Flow Graph is drawn must be [    c  ]

(a) Differential Equations (b) Algebraic equation (c) Algebraic equation in the form of cause- and effect relations (d) Differential Equations in the form of cause- and effect relations

2.  The shape of rotor in control Transformer is [   b  ]

(a) Drag cup (b) cylindrical (c) Toothed rotor (d) Dumb-bell

3.  In a 2Φ AC servo motor , the rotor has a resistance ( R) and reactance ‘X’ , Torque -speed characteristics of the servo motor will be linear provided that ______ [   a ]

(a)X/R<<1 (b) X/R>>1 (c) X/R=1 (d) X2 = R

4. Synchro is a/an   [ c]

(a) Frequency transmitter (b) Electronic rectifier

(c) Electromagnetic transducer (d) Electro mechanical device

5.  In Masons gain formula Δ is calculated as [ A]

a) 1-(sum all individual loop gains) +(sum of gain products of all combinations of 2 nontouching loops)-(sum of gain products of all combinations of 3 nontouching loops)+……….

b) 1+(sum all individual loop gains)+(sum of gain products of all combinations of 2 nontouching loops)+(sum of gain products of all combinations of 3 nontouching loops)+……….

c) (sum all individual loop gains)+(sum of gain products of all combinations of 2 nontouching loops)+(sum of gain products of all combinations of 3 nontouching loops)+……….

d) (product all individual loop gains)-(sum of gain products of all combinations of 2 nontouching loops) +(sum of gain products of all combinations of 3 nontouching loops)-……….

SECTION-II: Fill in the blanks

1.      The functional operation of the system can be visualized more readily by examining the Block diagram than by examining the physical system itself.

       2.Mason’s gain formula is  __________

                              

                               UNIT-III: TIME RESPONSE ANALYSIS

1.  An on-off controller is [C ]

(a) P controller (b) Integral controller (c) Non linear controller (d) PID controller

2.  Damping is proportional to _____________ [ D ]

(a) Gain (b) 1/Gain (c) √ (gain) (d) 1/√ (gain)

3.  The time response T is an indicative of     [ a]

a) how fast the system tends to reach a final value b) how slow the system is

c)how fast the system output decays to zero value d) the system’s steady state behavior

4.  A large time response corresponds to a     [  a ]

a) sluggish system b) faster system c) overdamped system d) underdamped system

5.Knowledge of the transfer function is necessary for the calculation of [b ]

a) time constant b)output for a given input c) order of a system d)none of these

6. A PID controller is an [c ]

a) Proper integral derivative control b) Parameter Intermediate defined control

c) Proportional Derivative control d) Pulsating Interval dependent control

SECTION-II: Fill in the blanks:

        1. The formulae for steady state error by using dynamic error co-efficient

  Ess=K₀ R (t) + k₁ R¹ (t) + k₂/2! R¹¹ (t) +….

        2. Delay time, Td=  (1+0.7ζ)/ωn

      3. Static error Coefficient  method cannot give the error if the input is other than standard input.

      4.For a second order Differential Equations if the damping ratio is unity then the poles are

    Equal & same

      5. In proportional control, the actuating signal is  proportional to the error signal.

      6. The time required for the response to reach and stay within a particular percentage of final value is called Settling time

     7. The inverse laplace transform of the transfer function of a system is its  impulse response

      8. The  steady state error constants describes the ability of a system to eliminate steady state errors.

      9. Steady state error for a unit ramp input for a type-0 system is infinity

                    

                   UNIT-IV: STABILITY ANALYSIS IN S-DOMAIN

1.  The starting points for root loci. are [a ]

(a) Open loop poles (b) closed loop poles (c) Open loop zeros (d) closed loop zeros

2.  In Routh Hurwitz’s criterion, if all the elements in one row are zero, then there are [c]

 (a) All the roots lies in LHS (b) Lies in RHS

(c) Pair of conjugate roots lies on Imaginary axis (d) insufficient data

3.  A control system is stable if [a ]

a) all the roots of the characteristic equation has negative real parts

b) all the roots of the characteristic equation has positive real parts

c) any root of the characteristic equation has negative real part

d) any root of the characteristic equation has positive real part

4.  If there are repeated roots of the characteristic equation on the jw-axis, the system is [d ]

a) conditionally stable b) oscillatory c) stable d) unstable

5.  The roots of the characteristic equation are the same as the poles of the [a ]

a) closed loop transfer function b)open loop transfer function

c)forward path transfer function d) none

6. The technique which gives transient response quickly as well as stability information is [d ]

a) Nyquist plot b) Routh-Hurwitz criteria c) Bode plot d) Root locus

SECTION-II: Fill in the blanks:

1.      The routh’s stability criterion gives information only Absolute  stability of a system but fails to indicate the  Relative stability of a system.

2.      Root locus diagram can be used to determine Relative stability.

3.      The root loci of G(s) H(s) =k(s+1) (s+3)/s(s+2) (s+6) no of asymptotes of 1

4.The angle condition of an open loop Transfer function is  G(s) H(s) =+ (2q+1) 180, q=0, 1, 2,…

5.The no of poles lies at the origin of open loop Transfer function is called as________

6.The root locus is Symmetrical about the real axis



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III Year DSP BITS

                            Digital Signal Processing (DSP)

                                   JNTUH Second mid Bits

                                                 UNIT-5

SECTION-I: Multiple choice questions

1.  The impulse invariant mapping and bilinear mapping are  [  d  ]

( a ) both are many-to-one mapping ( b ) both are one-to-one mapping

( c ) one- to- one and many-to-one mapping respectively

( d ) many-to-one and one- to-one mapping

2.  In Chebyshev approximation, at the cutoff frequency,the normalized magnitude response has a value of      [ a]

3.  The two properties which are preserved in analog to digital transformation are [  c  ]

( a ) linearity and stability ( b ) linearity and causality

( c ) stability and causality ( d ) time in variant and linearity

4.  A mapping from the S-Plane to the Z-Plane called [ c]

(a) Laplace Transform (b) Z-Transform (c) Bilinear Transform (d) None

5.  In which filters exhibit equiripple behavior in the pass band and a monotonic characteristics in the stop band [ b ]

(a) Butterworth (b) Type I Chebyshev (c) Type 2 Chebyshev (d) Elliptic

6.  How many types of chebyshev filters are there?   [ b  ]

(a) 4 (b) 2 (c) 3 (d) 6

7.   The digital frequency in bilinear transformation is [ b ]

8.  In chebyshev filter, the alternation constant is [a ]

9.  The ratio (Ω₂)/(Ω₁) for impulse invariant transformation is   (a)

_(a)      (W₁) / (w2)   (b) (w₁)/(w)   (c) (w)/(w₂)   (d) (w₁)/(w₂)

10.  The normalized magnitude response of chebyshev    type-I filter has a value of ________ at the cutoff frequency Ω  (c )

Section-II: Fill in the blanks

1.In impulse invariant mapping the left half poles of s-plane are mapped into

 Interior  of unit circle in z-plane

2. The poles of the butterworth transfer function symmetrically lies on an unit circle in s-lane with

angular spacing of  π/N

3. The frequency response of the Butterworth filter Decreases monotonically with  Increasing Ω and as the filter order increases, the transition band become narrower.

4. Impulse invariance method is not suitable for  HIGH PASS

5.  Bilinear Transformation can pressure the magnitude response of an analog filter, but the phase response of the analog filter cannot be pressured

6. A linear phase analog filter cannot be transformed to a linear phase digital filter using bilinear transformation.

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III year Digital communications bits

                                     Digital    communications

                                                Unit-1

 1.The advantage of Manchester encoding is [    c ]

A) less band width requirement B) less bit energy required for transmission

C) less probability of error D) less bit duration

2. The Nyquist's rate of sampling of an analog signal S(t) for alias free reconstruction is 5000samples/sec. For a signal x(t) = [S(t)]2 ,the corresponding sampling rate in samples/sec is  10,000

3. The sampling rate in Delta Modulation is More than PCM.

                                           Uniit-2

1.  The minimum band width required to multiplex 12 different message signals each of band width 10KHz is [   b]

A) 60KHz B) 120KHz C) 180KHz D) 160KHz

2.  Companding results in [   c]

A)More S/N ratio at higher amplitudes of the base band signal

B) More S/N ratio at lower amplitudes of the base band signal

C) Uniform S/N ratio throughout the base band signal

D) Better S/N ratio at lower frequencies

3.  A uniform quantizer is having a step size of .05 volts. This quantizer suffers from a maximum quantization error of [     b ]

A) 0.1V B) 0.025 V C) 0.8 V D) 0.05 V

4.  Granular Noise in Delta Modulation system can be reduced by   [ c  ]

A) using a square law device B) increasing the step size

C) decreasing the step size D) adjusting the rate of rise of the base band signal

5.  Tapped Delay Line Filter  is used as a Predictor in a DPCM transmitter.

6. A signal extending over -4v to +4v is quantized into 8 levels. The maximum possible quantization error obtainable is 0.5v V.

7. The sampling rate in Delta Modulation is more than PCM.

                                                  Unit-3

 1.In 8-PSK system, adjacent phasors differ by an angle given by ( in degrees) [ a   ]

A) n/4 B) n/8 C) n/6 D) n/2

2.  Band Width efficiency of a Digital Modulation Method is    [ c  ]

A) (Minimum Band width)/ (Transmission Bit Rate)

B) (Power required)/( Minimum Band width)

C) (Transmission Bit rate)/ (Minimum Band width)

D) (Power Saved during transmission)/(Minimum Band width)

3.  The minimum band width required for a BPSK signal is equal to [d   ]

A) one fourth of bit rate B) twice the bit rate C) half of the bit rate D) bit rate

4. In Non-Coherent demodulation, the receiver     [      b      ]

A) relies on carrier phase B) relies on the carrier amplitude

C) makes an error with less probability D) uses a carrier recovery circuit

5. Non-coherent detection of FSK signal results in   More Probability of error

6. The phases in a QPSK system can be expressed as  0, 90, 180,270

7. The Synchronization is defined as The use of same clock to maintain the order of transmission

                                                          Unit-4

1.  The Auto-correlation function of White Noise is [  a]

A) Impulse function B) Constant C) Sampling function D) Step function

2. A Matched filter is used to   minimizes the probability of error

3. The bit error Probability of BPSK system is same that of QPSK.



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III Year MP and MC Bits

                                              

                                  Micro processors and micro controllers

                                    JNTUH mid bits

                                              

                                                           UNIT-1

 1.Which of the following register is not present in EU( Execution Unit) of the 8086 microprocessor? [   d]

a. SP b.BP c.SI d.IP

2.  Which signal is used to demultiplex the Adress bus of 8086 [   d  ]

a. BHE b.LOCK c.READY d.ALE

3.  Which of the following signal is used to control the direction of dataflow of bus transcievers [  a ]

_ __ ____

a.   DT / R b. M / IO c. DEN d.ALE

4.  Which of the following signal belongs to maximum mode only [  c  ]

____ _____ _____ ____

a.   RD b. TEST c. LOCK d. DEN

5.  Which of the following pair of registers is invalid [ a ]

a. CS:SP b. SS: SP c. DS:BX d. ES:DI

6.  Which of the following flags is used for single stepping [   c]

a. Direction Flag b. Interrupt Flag c.Trap Flag d. Overflow Flag

7.  Which of the following are the three basic sections of a microprocessor unit? [   b]

(A) operand, register, and arithmetic/logic unit (ALU)

(B) control and timing, register, and arithmetic/logic unit (ALU)

(C) control and timing, register, and memory

(D) arithmetic/logic unit (ALU), memory, and input/output

8.  Which bus is a bidirectional bus? [  b ]

(A) address bus (B) data bus (C) address bus and data bus (D) none of the above

9.  Direction flag is used with [  a]

(A) String instructions (B) Stack instructions

(C) Arithmetic instructions (D) Branch instructions

10.  What does microprocessor speed depends on? [  c ]

(A) Clock (B) Data bus width (C) Address bus width (D)size of register

11.  A register capable of shifting its binary information either to the right or the left is called a[ c] (A)parallel register (B) serial register (C) shift register (D) storage register

12.  What is meant by Maskable interrupts? [  b ]

(A) An interrupt which can never be turned off

(B) An interrupt that can be turned off by the programmer

(C) An interrupt which can be turned off automatically

(D) none

13.  In a DMA write operation the data is transferred [  a]

(A) from I/O to memory (B) from memory to I/O

(C) from memory to memory (D) from I/O to I/O

                                       Fill in the blanks

1.      Flags are divided into control flags & conditional flags

2.      Data bus is used for  sending and receiving data between CPU and other devices

      3. The function of instruction CLC is to  reset the carry flag to zero

3.      ALE( address latch enable) signal is provided by 8086 to demultiplex the AD₀-AD₁₅ into A₀-A₁₅ & D₀-D₁₅ using external latches.

4.      The part of operating system which is loaded in RAM during powerup from harddisk or floppy disk is known as  DOS(disk operating system)

      6.The cycle required to read from memory is called  Machine Cycle.

      7.The address available at 8086 pins is called  Physical Address

      8. The Condition which makes CPU execute next instruction after WAIT instruction is

 TEST Becomes Low

                                                    UNIT-2

1.  Which of the following register holds the address of I/O port of I/O instructions of 8086 [ b   ]

         a. BX    b.DX     c.SI     d.DI

2.  What do the symbols [ ] indicate?               [ c]

(A) Direct addressing (B) Register Addressing

(C) Indirect addressing (D) None of the above

  Fill in the blanks

3. The instruction MOV AX,BX gives that   the contents of register BX are copied to AX and stored in it

4. The instruction MOV 1234[BX],3456H is   Six (6) bit (opcode) Instruction.

                                                              UNIT-3

1.  The advantage of memory mapped I/O over I/O mapped I/O is, [ d   ]

(A) Faster (B) Many instructions supporting memory mapped I/O

(C) Require a bigger address decoder (D) All the above

2.  Which pins are general purpose I/O pins during mode-2 operation of the 8255? [  a ]

(A) PA0 – PA7 (B) PB0-PB7 (C) PC3-PC7 (D) PC0-PC2

3. An example for a D/A converter is  IC 1408,DAC0830/DAC0831/DAC0832

4._Port A port of 8255 can be programmed in three modes: mode 0, mode 1, mode 2.

5.The modes used in display mode are  left entry mode (type wroter mode) & right entry mode (calculator type mode)

                                                         UNIT-4

 1.If a memory block uses address range 10000H to 2FFFFh then its capacity is [  b    ]

    a. 64KB b.128KB c.256KB d.512KB

2.  Which Command word of 8259 is used masking interrupts [  c  ]

a. ICW1 b.ICW2 c.OCW1 d.OCW2

3. During block transfer mode , the completion of data transfer is indicated by  . TC Flag

4.The  Seventh (7) bit of the Control word register of 8257 is used for enabling auto load facility.

5.The Instruction of 8257 used to disable CPU address is  AEN.

6.The number of 8259s required to service 64 interrupts is Nine (9)

7.. The command word used to differentiate master and slave is ICW3.

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